Bitmaps distort any type or vector at the bounding box when exporting to PDF

I've uploaded both the original Corel X6 file (latest service pack) and the PDF x-1A made from that file.

There are three bitmaps in crossword puzzle; a car, money bags and a Go Pro. These graphics also have drop shadows that have been broken apart (though I find that makes no difference). You will notice the type and crossword boxes are distorted where ever the bounding box of either the bitmap or the dropshadow (also a bitmap) touches a vector graphic or typeface.

Here's a google docs link to the two files. https://drive.google.com/?urp=https://www.google.com/&authuser=0#folders/0BxbUH1RqOA3Ud1ZCZmlqaGplNG8

Thanks, Lorne

Had a look at that URL, but I'm getting a request for a user name and password. I'm not sure how google drive works, but you probably need to create a separate folder and mark it as public to make it visible to others.

try this link,

https://drive.google.com/file/d/0BxbUH1RqOA3Ua09iNTdvd2RsWm8/edit?usp=sharing

https://drive.google.com/file/d/0BxbUH1RqOA3UemwzMzdfSVFWTTg/edit?usp=sharing

I also made it public, so anyone on the web can view, so hopefully that works?

OK, I now see what you are describing.

What happens is that Corel is not allowed to put transparent bitmaps in PDF-X/1 or PDF-X/3 files, and therefore must do the best it can by replacing each of them with an opaque bitmap. Consequently, it has incorporate everything immediately behind the transparent area into the opaque bitmap.

You can see exactly what it has done if you import the PDF into a new CorelDraw document. Ungroup the objects and move the moneybags aside. You will see it has created two bitmaps, both opaque, which together represent the original transparent bitmap, its drop shadow and their immediate background:

This doesn't really work, because the opaque bitmaps gets created at 300dpi but the vector objects behind it, if printed on an imagesetter, will be rendered at maybe 1200 or 2400dpi. Consequently, the line thicknesses do not match.

You can probably improve matters by increasing the rendering resolution (in X6 it is configured at tools > options > document > page size > rendering resolution but this may not completely solve the problem. Even if you choose a high enough resolution to make the thicknesses look the same, there is a danger that the image could be rendered as RGB and the background as CMYK, or vice-versa. So the possibility is that you will notice a colour change even if you manage to fix the line thickness.

The way I would deal with this is to selectively create my own bit images.

• Save a permanent copy of your file before doing this. You may need to revert to it if the design is revised in future.
• Create a second layer, in front of everything else
• Move all the text (just the text, not their tiles) to that front layer
• Select everything on layer 1 and convert it to bitmap at 600 or 1200 dpi

Now you have everything rendered as a bitmap, except the text which will be rendered at full imagesetter resolution -- so the printed result should be more like what you now see on the screen.

Incidentally, there's an easy way to move that text to layer 2.

Edit > Select All > Text > Cut then select layer 2 and paste. Then you can lock layer 2 so that edit > select all now selects only layer 1 to convert to bitmap.

Here's a screen dump from an 800% zoom of the resulting PDF:

Ideally you should add an extra step -- set the pixel grid to the resolution you plan to use for the bitmap and snap all horizontal and vertical lines to that grid. That should avoid the antialiasing differences on the thicknesses some of the lines -- though I doubt if you'd see them without magnifying the print.

harryLondon said:

Corel is not allowed to put transparent bitmaps in PDF-X/1 or PDF-X/3 files

Also, transparent bitmaps in  PDF-X/3/acrobat8 files not works fine here.